1. Field of the Invention
The present invention relates to database systems. More specifically, the present invention relates to a method and an apparatus for performing cost-based optimizations of authorization checks in database systems.
2. Related Art
Many organizations use Access Control Lists (ACLs) to control an entity's access to particular objects within database systems. An ACL typically comprises a list of Access Control Entries (ACEs) that specify the privileges granted and/or denied to a given entity. ACLs may be stored in various formats, such as in eXtensible Markup Language (XML) files, or within database tables. Each format has advantages and disadvantages related to speed, resource consumption, and security.
When implementing a database system with ACLs, database administrators typically determine which ACL-based security model he or she will use. There are multiple ways to evaluate the ACLs involved in a given security model. However, in this situation, it can be problematic to determine which evaluation method should be used for a given request.